1. Field of the Invention
The present invention relates to data storage devices, or disk drives, for storing digital information, and more particularly, to a one-piece magnet return path assembly for a voice coil motor in a disk drive.
2. Description of the Prior Art
Disk drives often employ voice coil actuators for positioning the read/write heads of the disk drive over the surfaces of a disk-shaped storage media. Magnetic flux for the voice-coil motor is typically generated by a magnetic circuit comprising a return path assembly and a pair of magnets. The return path assembly is usually comprised of a top plate, a bottom plate, and a plurality of standoffs. The standoffs hold the top and bottom plates apart at a predetermined distance to form an air gap for receiving a coil coupled to one end of the actuator. Magnets are typically bonded to the inner walls of both the top and bottom plates. The top and bottom plates, along with the standoffs, form a flux return path for a magnetic field generated by the top and bottom magnets. The magnetic flux within the air gap between the magnets induces torque on the actuator in response to an electric current in the actuator coil.
In prior art disk drives of the type described above, the top and bottom plates and the standoffs are formed separately from a magnetically permeable material, such as a low carbon steel. These separate components are then assembled together using suitable hardware. U.S. Pat. No. 5,313,124 discloses such a prior art return path assembly.
Unfortunately, these prior art return path assemblies increase the assembly time and manufacturing costs of a disk drive, since the various components must be purchased separately, along with suitable hardware, and then assembled together in the disk drive. There is a need, therefore, for a more cost-effective magnet return path assembly for a disk drive that overcomes the disadvantages of prior art assemblies. The present invention satisfies this need.